@inproceedings{hu2019read+,
  title={Read+ verify: Machine reading comprehension with unanswerable questions},
  author={Hu, Minghao and Wei, Furu and Peng, Yuxing and Huang, Zhen and Yang, Nan and Li, Dongsheng},
  booktitle={Proceedings of the AAAI Conference on Artificial Intelligence},
  volume={33},
  pages={6529--6537},
  year={2019}
}